Rattles/squeeks can be such a pain to locate! If you rev the engine, or run it at various speeds, can you re-create it in the garage?
Only suggestion other than that is to take a helper on a ride and try to have the helper locate the rattle while you drive.
Good luck ... I have a squeek in my back seat that I simply can't find. It only happens around 70-80mph on the freeway, and I can't reproduce it in the garage. I even put my daughter in the back seat to find it, but she couldn't locate it, either!
If you always do what you've always done,
You'll always get what you've always got
http://www.classic-mustang.net/johnpro
Only suggestion other than that is to take a helper on a ride and try to have the helper locate the rattle while you drive.
Good luck ... I have a squeek in my back seat that I simply can't find. It only happens around 70-80mph on the freeway, and I can't reproduce it in the garage. I even put my daughter in the back seat to find it, but she couldn't locate it, either!
If you always do what you've always done,
You'll always get what you've always got
http://www.classic-mustang.net/johnpro